US2443830A

US2443830A - Method of assembling the power section of radial engines

Info

Publication number: US2443830A
Application number: US508992A
Authority: US
Inventors: Jr Thomas Mcdaniel
Original assignee: Individual
Current assignee: Individual
Priority date: 1943-11-04
Filing date: 1943-11-04
Publication date: 1948-06-22
Anticipated expiration: 1965-06-22

Description

June; 22, 1948.

Filed Nov; 4, 1943 T. M DANIEL, JR METHOD OF ASSEMBLING THE POWER SECTION OF RADIAL ENGINES a Sheets-Sheet 1 INV'ENTOR. Thomas McDaniel, dr.

ATTORNEY June 22, 1948.

T. M DANIEL, JR METHOD OF ASSEMBLING THE POWER SECTION OF RADIAL ENGINES Filed Nov. 4, 1943 6 Sheets-Sheet 2 7 INVENTOR.

Thomas McDaniel, Jr.

ATTORNEY June 22, 1948. 'r. M DANIEL, JR

' METHOD OF ASSEMBLING THE P SECTION OF RADIAL ENGIN 6' Sheets-Sheet 5 Filed Nov. 4, 1943 INVENTOR. Thomas McDameLJr.

WW, I

' ATTORN 7 Ely/8 June 22, 1948. McDAN|E| JR 2,443,830

METHOD OF ASSEMBLING THE POWER SECTION OF RADIAL ENGINES Filed Nov. 4, 1943 6 Sheets-Sheet 4 INVENTOR. Thomas McDomel, Jr.

ATTORNEY June 22, 1948. 'r. M DANIEL, JR 2,443,830

j METHOD OF ASSEMBLING THE POWER 7 SECTION OF RADIAL ENGINES 6 Sheets-Sheet 5 Filed NOV. 4, 1943 INVENT OR.

Thomas McDanieLJr.

ATTORNEY June 22, 1948. T. McDANlEL, JR 2,443,830

METHOD OF ASSEMBLING THE POWER SECTION OF RADIAL ENGINES 6 Sheets-Sheet 6 Filed Nov. 4, 1943 INVENTOR. 122 Thomas McDameLJr.

Patented June 22, 1948 METHOD OF ASSEMBLING THE POWER SECTION OF RADIAL ENGINES Thomas McDaniel, Jr., Cincinnati, Ohio Application November 4, 1943, Serial No. 508,992

7 Claims. 1

.This invention relates to amethod of assembling the power section of internal combustion engines of the radial type. T An object of the invention is to provide a simple, highly effective method for simultaneously aligning the front and rear crank shaft assemblies with reference to the front and rear cranks of the crankshaft of an internal combustion engine ofthe radial type characterized by a double bank of cylinders.

Another object of the invention is to teach a new and novel method of assembling the power section of an internal combustion engine of the Fig. 4 is a top view of an adjustable adapter for a crankcase holding pad.

Fig. 5 is a side view of the adapter of Fig. 4. Fig. 6 is an end view of the adapter of Fig. 4. Fig. 7 is a top view of one form of crankcase holding pad which comprises adetail of the invention.

Fig. 8 is a side view of the pad of Fig. '7. Fig.9 is a top view of another form of crankcase holding pad.

Fig. 10 is a side view of the pad of Fig. 9.

Fig. 11 is a front end view of the cradle of Fig. 1 with the center crankcase section of Fig. 2 mounted therein. i

Fig. 12 is a top view of the center section of the crankshaft of a radial engine. f

Fig. 13 is a top view of a center crankshaft handling tool which comprises a detail of the pres entinvention. a

Fig. 14 is a side view of the crankshaft of Fig. 12 mounted in the tool of Fig. 13.

Fig. 15 is a top view of Fig. 11.

Fig. 16 isa front View of a center crankshaft retaining. tool which comprises a detail of the present invention. I

'Fig. 17 is a top view of the tool of Fig. 16. i

Fig. 18 is an end View of aconnector rod assembly wherein the master and various articulating rods are yieldingly held in an extended position by means of i a rod spacing tool which comprises a detail of the invention.

Fig. 19 is a separated view of the component parts of an articulate rod clamp.

Fig. 20 is an end view, partially separated, of a master rod clamp.

Fig. 21 is a top view of the clamp of Fig. 20.

Fig. 22 is a View similar to Fig. 11 but with the rod assembly of Fig. 18 mounted on the forward crank of the crankshaft.

Fig. 23 is a top view of Fig. 22.

Fig. 24 is a perspective view of a master rod stabilizing tool comprising a detail of the invention.

Fig. 25isa right side view of the engine assembly of Fig. 22, but with the front and rear crankshafts mounted onto the center crankshaft and ready to be checked for axial alignment.

Fig. 26 is a side view of a crankshaft engaging clamp.

Fig. 27 is a view similar to Fig. 25 but with the dial gauges released and with the front and rear crankshafts clamped for tightening of said crankshafts on and relative to the center crankshaft.

Fig. 28 is a top view of Fig. 26 but with the forward and rear crankshaft clamps released, and showing the rear main bearing, and the front and rear crankcases ready to be mounted to the engine.

Fig. 29 is a separated view of an engine holddown tool comprising a detail of the invention.

Heretofore the power section of internal combustion engines of the radial type have been assembled around the crankshaft, the opposite ends of which have been alternately mounted in holding fixtures for facilitating assemblage of parts onto the free, or unheld end. Such procedure entaileda considerable amount of unnecessary handling of the engine being assembled with the result that highly skilled mechanics were required for the job. i

In sharp contrast to the methods and apparatus now used, my method and apparatus enable unskilled or semi-skilled labor to be used in lieu of the high priced, highly skilledlabor heretofore required, and in addition thereto the rate ofproduction may be increased elevenfold while the accuracy of the crankshaft bear-ing alignment is materially increased.

' For clarity of detail and understanding the present invention will be explained in terms of the procedure followed in fabricating the power section of an internal combustion engine of the radial type.

With reference to Figs. 1 and 2 the numeral 30 denotes a cradle or holding fixture for the central section 3| of the crankcase of a radial en- 3 gine. The cradle may comprise a pair of

complementary sections

32 and 33 secured together by means of bolts 3%, and wherein each section includes opposed side edges 35 and 36, and outturned foot portion 31 and an arcuate upper edge 38. A dovetail shaped slot 39, having a restricted throat portion Ml, is provided between the adjacentfaces of

sections

32 and 33 and in spaced parallelism with arcuate edge 38. The upper end of throat portion M3 is in open communication with edge 38 for facilitating attachment of adapter members 4| relative to arcua'te edge 38.

As disclosed in Figs. and 6, the adapter'members comprise a body portion i2 and an arcuately shape-d key element 43 which is complementary to and adapted to slideab'ly engage: the dovetail slot 39.

Each adapter member is adapted to locate a central crankcase holding pad 44 or i5, relative to a rcuate edge-38 of the cradle for engaging certain of the cylinder base openings provided in the lower or underside of the central section of thecrankcase. Each pad includes an outwardly protecting Tim- 01 lip t5 (Fig. 9) or a partial rim or lip 41 (Fig. 7), which are adapted to fit or extend into the cylinder base openings, as hereinafter more fully explained. The pads may be secured to their respective adapters by means of bolts, i i-vets or the like denoted generally by the numeral 58 (Fig. Each pad and its associated adapter may be fastened or locked relative to the periphery of edge 38 by means of loeki-ng screws "490, the lower ends of which engage edge 38. By loosening locking screws #90, the relative position of the various pads and their respective adapters may-be shift-ed along arcuate edge 38, for accommodating the different spacing of the cylinder base-openings of vari- 011s radial engines.

central section 31 of the crankcase of a radialengine comprises a "double row of stagge'red, semi-circular cylinder abase openings 49, 'disposed around the outer periphery of the case, as best illustrated in 15. The central crankcase holding pads M, havin'g full rims-or lips 46., are aligned relative to arcuate edge 38 of the cradle whereby to engage cylinder base openings tefts'and at (Fig. {1 5) whereas pads 45-, having partial lips or rims 'd'lgare a lignedm engage 'cylinner-

base openings

52, 53. 54, 55, whenthe'crankcase is lowered verti'eally f'rom the position of Fig. 2 into fixture on, where-by "to assume the position indicated in Fig. 11. Y

The 'crankcase will be -securely positioned cradle '35 by its cam weight and by 'the inter-- action between pads M "and 615 and their respectiiie "Cylinder base openin s,

As disclosed in Fig. 2, the central section of the crankcase is laterallydivid'ed 'by'means of a 'centra1 web 56, liaving a center crankshaft main searing opening i'vfdisposed therethrough. A *centralinain bearing race'retainer lip 58 is prov ed a'ro'un'd inc-st of the periphery of opening *5? "in' such 'a manner as to provide a rear crank clearance space =59.

The next step in the engine'a's'semblage is to mount the'cent'ral crankshaft Gil-and'th'e central "r'nain bearirig 6-! inbrankcase 3!. As disclosed "in "Fig. 12 the "central crankshaft comprises a forwardcrank portion E2 and "a rear crank portion 63. The crankshaft may be lifted into'mlace 'by'niea'ris'of'the moi-st illustratedidFigs. 13 and "Which'cohip'iiSs afront crank engaging loop Eb, a main bearingengagirfg loop 66, 4 a' 'connect-or element 61, and a pair of handles 68. The main bearing engaging loop preferably includes a depending lip 69 which is adapted to abut against forward face ii! of center main bearing 6| for determining the relative position of the tool on the bearing. By lifting on handles 68 one operaior may lift the crankshaft and insert the rear crank portion 63 through web opening 5'? and align the central mainbearing 51 relative to its seat until it abuts against lip '58. The cut away v clearance space 59 facilitates insertion of the rear -crank into the crankcase opening. After the crankshaft and crankshaft locking tool I! applied thereto;

The: locking tool. 1 comprises an arcuate central portion 12 which is adapted to fit over the upperportion of the central main bearing GI, and a pair of downwardly projecting legs 13 which engage the forward face of the inner race of the main bearing of the central: "crankshaft, and a pair of outwardly extending arms T4. The outer end of each of the arms M terminates in looking lugs 15 which are adapted to be inserted into a breather hole of crankcase 31 and then be turned by means-of actuator handle 16 whereby the eccentric end 1.! will engage the rear face of the crankcase for securely lockingthe tool and center crankshaft in the positiondisclosed. .in Fig. 11. I

The crankshaft may now be secured against rotation. relative to crankcase 31 by means of latch member 18 pivotally secured to the apex of the central. portion of tool 11.. Member TB is preferably dimensioned soas-to snugly fit between a pair of cap screws 19: and 8D threaded into the main bear-ingsupport or locking plate 8|. The crankshaft has now been securely mountedzrela tive to the central crankcase with the front and rear crank. portion '62 and. \63' respectively projecting from opposite sides thereof, as illustrated in Fig. 15.

The frontrand rear crank rod assemblies may now be mounted on, the front and rear cranks of the central crankshaft. In .order to facilitate ease of assembly and mounting the rod assemblies, means are. provided for releasably holding the various articulating rods 82 in. extended position relative to each other and to the master rod 83. Such means may comprise a flexible connector formed, of wire, rope, chain, or the like, denoted generally by the numeral 34,, and .a plurality of adjustable clamps which are adjustably secured to the flexible connector by means of plate '86 and screw '87. As illustrated in Fig. 19, plate '88 includes a flat portion 385 and a half rounded portion .386. The rounded portionis adaptedt'o clampingly'engage the flexible connector 84 and wedge it against the outer face of clamp '85 when screw 81, which extends through portion 385, is threaded into clamp 85. In this manner the various clamps 85 'are'securely, though releasably, "fastenedto connector member 84. Each clamp "85 is adapted to engage the outer or wrist pin end of an articulating rod, whereas a master clamp- 88 is adapted to engage "the outer'en'd of the master rod. -As illustrated in Figs. 20 and 21 the master clamp BB-comprises an inverted U shaped'housing'having one end, 89, "closed-and with the other endopen to facilitate endwise sliding of *said housing onto "the outer end of the master rod. The open end of the housing maybe closed *by means'of a :hinged looking gate 90 pivotallysecured as at a l to themouszing. A threaded stud 92 is secured to and carried by housing 89, said stud adapted to receive plate 86 and nut 93. It will be observed that once'the various clamps have been locked to flexible connector 84 at a desired connector rod spacing for a given engine, they will thereafter space the rods of all subsequent assemblies in exactly the same manner. A spring 94 is preferably provided between the opposite ends of the flexible connector, for a purpose hereinafter more fully explained.

An extended rod assembly, arranged as illustrated in Fig. 18, may be lifted, for mounting the assembly on the forward or rear cranks of the center crankshaft, by grasping the master rod intermediate its length. The flexible connector will maintain the various rods in their preselected extended relationship, as each rod is located within its respective cylinder base opening.

In order to moreaccurately locate the outer ends of the various articulator rods 82 relative to the cylinder base openings and to facilitate their reciprocatory action as the forward and rear crankshafts I 09 and I I3 are run in, a master rod stabilizing tool 91 (Fig. 24) may be utilized for aligning the master rod of a rod assembly relative to its respective cylinder base opening. This tool may be fabricated from a length of strap material formed to provide a pair of divergent legs 98 disposed in a common plane and a pair of downwardly depending legs 99. A cross strap I is provided between and interconnects the lower ends of legs 99. The ends of said strap are bent whereby to provide a pair of inturned hook-like members IOI. Each depending leg 99 may include a pair of spaced stud receptive apertures I03 whereas a stud receptive aperture I02 is provided through the apex of divergent legs 98. A

pair of half round bearing bars I04 are provided, each bar including a pair of outwardly projecting studs I05 which are adapted to be inserted into apertures I03 of legs 99. A spring I06 may be provided on studs I05 for normally urging the bearing bars away from their respective legs 99.

Aocidentaland/or unintentional withdrawal of studs I05 from their respective apertures may be precluded by threading a nut, not illustrated, onto the outer ends of the studs which project through the apertures in legs 99. I

Tool 9'! is adapted to be lowered onto and over the master rod whereby the hook members IOI will engage the opposite side edges of the rod and wherein stud 92 of the master rod bearing clamp 89 will project upwardly through aperture I02 after which a nut I01 may be applied for securely, though releasably attaching the tool to the master rod. As best illustrated in Figs. and 2? bearing bars I04 are adapted to abut against the periphery of cylinder base I08. It should be understood that a duplicate rod assembly will be provided for the front and rear cranks, and that the master rod of each assembly will be provided with a stabilizing tool 91.

The forward cranlshaft assembly, comprising forward crankshaft I09, split yoke H0, and counterbalance H2, may be secured to the forward crank portion 62 of the center crankshaft. The rear crankshaft assembly, comprising rear crankshaft H3, split yoke H4, and counterbalance H6, may be secured to the rear crank portion 63 of the center crankshaft, in a manner well known in the art. Cap screws I II and H5 may then be snugged down to facilitate alignment ofthe front and rear crankshafts.

A steady rest, comprising a pair of rollers II1 secured to and carrier by an arm II8, which in turn is secured to and carried by a vertically adjustable post 9, may be disposed beneath the overhanging portion of the forward crankshaft, and a dial gage I20 including a crankshaft contactor pin I2I may be operativelyassociated with the forward end I22 of the crankshaft. The forward crankshaft is thus mounted for rotation, however, before rotation may be effected it is first necessary to withdraw latch member 18 of locking tool 'II from its interfering relationship with cap screws I9 and 80. The latch may be returned to the inoperative position indicated in Fig. 16. The crankshaft may now be rotated for axial alignment, and if the alignment is not within predetermined allowable limits, the crankshaft may be adjusted on and relative to its crank portion of the center crankshaft. It will be observed that the various rods of the front and rear rod assemblies will reciprocate each within their associated cylinder base opening incident to rotation of the crankshaft. Flexible connectors 84, springs 94, and the masterrod stabilizing tools 91 cooperate in such a manner as to guide the free outer or wrist pin end of the various rods in substantially the same path they would describe if and when connected to their respective pistons.

In a similar manner the rear crankshaft is aligned relative to a true axis of rotation by means of dial gage I23 suitably positioned by means of a support rod I24.

After the front and rear crankshafts have thus been aligned, the dial gages I20 and I23 are moved to an inoperative position, the steady rest is lowered and the splined portion I25 is securely, though releasably engaged between jaws I26 and I2! of a two piece clamp I39 (Fig. 26) secured to andcarried by the upper end of post H9 (Fig. 27). The splined end I28 of the rear crankshaft is likewise engaged between jaws I82 and I29 of the two piece clamp I40, secured to and carried by the upper end of post I30. It will be understood that any suitable means may be provided for facilitating raising and lowering of posts 9 and I30, such as, by way of example, is disclosed in Figs. 25 and 26, wherein the crankcase cradle 30 is mounted upon an elevated platform I3I supported on legs I32 and I33. Posts II9 and I30 may telescopically engage legs I32 and I33 respectively, being maintained in extended condition by means of pins I34 which are insertable into apertures provided in and spaced along the length dimension of said posts.

After the clamps have thus been secured to splined portions I25 and I28 of the'front and rear crankshafts respectively, capscrews III and H5 may be tightened by means of wrenches I35, for locking said crankshafts to the center crankshaft. Clamps I39 and I40 may now be released and supporting post I30 lowered for disposing it in a non-obstructing position. The steady rest II8 may then be moved to a front crankshaft supporting position and dial gage I20 associated with end I22 thereof, after which the crankshaft is rotated and rechecked for axial alignment. If the alignment is proper support post H9 may be lowered, however if the crankshaft is out of alignment the rear post I30 is raised, clamps I39 and I40 applied, cap screws III and H5 loosened and the aligning procedure repeated.

It should be noted that thus far the engine being built has been supported solely by means of cradle inwhich it has beenv held secure by reason of its inherent weight. At this point in; the engine assembly it is preferable, though not essential, that center crankcase 3f be locked, orotherwisepositively secured to the cradle, before. the. front. and rear crankcases are assembled. This may be expeditiously accomplished by meansof the clamping means, denoted gen- .erally by the numeral Ml (Figs. 28 and 2.9), comprises a length of cable I42, or the like, one end of which is pivotally secured to pin H3: .01" cradle 3b- ;and the. opposite end of which terminates in a cam member [44, including a hand grip portion dbl. A plurality of holding pads M5, each including an outwardly projecting arcuate lip li l'ti, :are secured to and carried by cable F42; said pads being laterally spaced by a dimension equal to the spacing of the cylinder base openings. Arcuate lips 145 are adapted to engage a portion of the periphery of type cylinlder base openings it], 1'48 and I49 when cam MA .is associated with and locked relative to earicuate slot. 39.

After the engine assembly has thus been made fast: to cradle 3B, the master rod stabilizing tools 91 may be removed along with the rod holding means :89.

The rear main bearing outer race and roller retainer I50 may he slipped over :the rear main bearing inner raceway l5! (Fig. 28), after which the front and rear crankcases E52 and I53 re spectively, may be assembled. Tool H may be removed through the cylinder base openings, after :the crankshaft assembly has been secured against accidental .or unintentional removal from the engine.

The followingsequence of operations may then beperformed in order to complete assembly of the power section, to .Wit: The rear. cam drive gear may be installed and the valves timed, after Which-the. rear crankshaft cam gear thrust nut, locking screw and cotter pin (not illustrated) may be added, after which the following parts may he installed: :tai-l shaft drive gear, spring and locking ring; section .of engine including supercharger, acces= sory drive, oil pump and kindred items; front seal-retainer; bull gear, after which the engine maybe timed; bull gear thrust nut; nose section including propeller shaft; nose section wiring ring. The motor hold down clamping means ht! maynow be released and the top five pistons and their associated rings installed in the top five icylindcr openings. The top cylinders. may then be installedfollowed by the pushand rocker arm assembly of a radial engine.

From the foregoing it will be observed that I have provided a simplified method .of assembling an internal combustion engine of the radial type .as well as apparatus for practicing said method. It. be understood that the fixture may be portable or fixed, without effecting its emciency, depending upon. the circumstances under which it is to be used.

front super charger housing; rear The hereinabove described method of assembling a radial engine makes it. possible, for the first time,. to eificiently utilize semi or unskilled labor, since. both, ends of the center crankshaft are always freely accessible, thereby enabling an operator .to do but one or two operations as contribution toward assemblage of the engine. 'This is in sharp contrast. to the methods currently employed. wherein a few highly skilled mechanics build, or assemble em entire engine. Where formerly five skilled mechanics required 7 hours to assemble five radial engines, using my method five unskilled mechanics can assemble six radial engines in but so minutes. In other words, :56 engines can be assembled where five are now assembled.

Another decided advantage of my method over those currently used relates to the problem of aligning the front and rear crankshafts. The present method of pie-aligning the front and rear .crankshafts relative to the center crankshaft using lining bars maybe dispensed with and the front and rear crankshafits may now be simultaneously aligned with dial gages, thereby insuring more accurate alignment than heretofore possible. This may be done since the front and rear crankshafts are both exposed and easily accessible at the same time, see Figs. 15', 23, 25 and 27.

It will be observed that in those instances when dial gages are not available for checking the axial alignment of the front and rear crankshafts Hi9 and 113 respectively, it is, nevertheless, possible tov .quite accurately align the front and rear crankshafts in the following manner. After the front and rear cran'ks'hafts have been mounted and snugged onto the front and near cranks of the center crankshaft till, the front and rear crankcases may be mounted over the front and. rear vcrankshafts and secured to the center crankcase. During thisprocedure the front and rear crankshafts may be :aligned relative to the main bearing retainers of the front, center and rear cran'lscases, a'fter Whichisaid.crankcases may be removed without disturbing the axial alignment of the now aligned front and rear crankshafts. Cap screws Hi and M5- may now be tightened for locking the front and rear crankshafts in theiraxially aligned position relative to the center crankshaft. The front and rear crankcases may then be re-assernbled for completing the crankcase assembly. It will be us derstood that the front and rear connector rod assemblies will "be associated with their respective front and rear cranks of the center crankshaft before the front and rear crankcases are assembled.

It should be noted that certain modifications and changes in the structural details of the devices may be made, Within the scope of the appended claims, without departing from the'spirit of the invention.

What isclai-med is:

l. The method of'assembling thepower section of an internal combustion engine of the radial type which is characterized by a double bank of cylinders, and which-includes athree piece crankshaft comprising front, center and rear portions, and a three piece crankcase comprising front, center and rear portions, which methodcomprises the steps of securing the center crankcase portion inan upstanding position, of mounting the center crankshaft in thecenter crankcase with the front and rear cranks thereof projecting outwardly from t e respective front and rear faces of said crankcase, of mounting the front and rear connector rod assembliesontothe front and rear cranks respectively, of mounting the front and rear crank-shafts onto the front and rear cranks of the center crankshaft respectively, and of then mounting the front and rear crankcases over and in housing relatio-nshipflwith their respective crank shafts and in abutting relationship with said center crank case for completing the crankcase assembly.

2. The method of assembling the power section of an internal combustion engine of the radial type which is characterized by a double bank of cylinders, and which includes'a three element crankshaft comprising front, center and rear portions, and a three element crankcase comprising front, center and rear portions, which method. comprises the steps of securing the center crankcase in an upstanding position, of mounting the center crankshaft in the center crankcase where'- by the front and rear cranks thereof project outwardly from the front and rear faces respectively of said crankcase, of mounting the front and rear connecting rod assemblies onto the front and rear cranks, of mounting the front and rear crankshafts onto the front and rear cranks of the center crankshaft, of simultaneously checking the axial alignment of the front and rear crankshafts, of adjusting said crankshafts for correct axial alignment, of locking the axially aligned front and rear crankshafts to the central crankshaft, and of then mounting the front and rear crankcases over their respective crankshafts and onto the center crankcase for completing the crankcase assembly.

3. The method of axially aligning the front and rear orankshafts of an internal combustion engine of the radial type which is characterized by a double bank of cylinders, and which includes a three element crankshaft comprising front, center and rear portions, and a three element crankcase comprising front, center and rear portions, which method includes the steps of mounting the center crankshaft in the center crankcase, of mounting the front and rear connector rod assemblies onto the front and rear cranks of the center crankshaft, of mounting and snugging the front and rear crank-shafts onto the front and rear cranks of the center crankshaft, of mounting the front and rear crankcases over the front and rear crankshafts, of aligning said front and rear crankshafts relative to their respective crankcases as said crankcases are mounted onto the center crankcase, of removing said front and rear crankcases without disturbing the axial alignment of the front and rear crankshafts, of then looking said axially aligned crankshafts relative to said center crankshaft, and of then replacing said front and rear crankcases for completing the assembly.

4. The method of assembling the power section of an internal combustion engine of the type which is characterized by a "double bank of cylin ders, and which includes a three element crankshaft comprising front, center and rear portions, and a three element crankcase which comprises front, center and rear portions, which method comprises the steps of securing the center crankcase in an upstanding position, of mounting the center crankshaft in the center crankcase whereby the front and rear cranks of said crankshaft will extend outwardly of and be freely and simultaneously accessible from the respective front and rear sides of the center crankcase, of securing said center crankshaft to the center crankcase 10 against accidental or unintentional displacement therefrom, of mounting the front and rear connector rod assemblies with the variousarticulating and master rods in extended positions onto the front and rear cranks respectively whereby each of said rods will be spaced apart by adimension corresponding to the spacing of the cylinder base openings of the crankcase, of mounting'and snugging the front and rear crankshafts onto the front and rear cranks of the center crankshaft, of aligning the master rod of each connector rod assembly relative to its respective cylinder base opening in the center crankcase and for guiding said rod and the articulating'rods of the assembly relative to their respective cylinder base openings as their respective crankshaft is rotated for purposes of alignment, of simultaneously checking the axial alignment of the front and rear crankshafts, of locking said axially aligned crankshafts relative to the center crankshaft, and of then mounting the front and rear crankcases over their respective crankshafts andonto the center crankcase for completing the crankcase assembly.

5. The method of axially aligning the front and rear crankshafts of an internal combustion engine of the radial type which is characterized by a double bank of cylinders, and which includes a three element crankshaft comprising front, center and rear portions, and a three element crankcase comprising front, center and rear portions, which method includes the steps of mounting the center crankshaft in the center crankcase, of mounting the front and rear connector rod assemblies onto the front and rear cranks of the center crankshaft, of mounting and snagging the front and rear crankshafts onto the front and rear cranks of the center crankshaft, of mounting the front and rear crankcases over the front and rear crankshafts, of aligning said composite crankshaft by rotating the front and rear elements thereof relative to their respective crank cases, of removing said front and rear crankcases without disturbing the axial alignment of the front and rear crankshafts, of then looking said axially aligned crankshafts relative to said center crankshaft, and of then replacing said front and rear crankcases for completing the assembly.

6. The method of assembling the power section of an internal combustion engine of the radial type which is characterized by a double bank of cylinders, and which includes a three piece crankshaft comprising front, center and rear portions, and a three piece crankcase comprising front, center and rear portions, which method comprises the steps of securing the center crankcase portion in an upstanding position, of mounting the center crankshaft in the center crankcase with the front and rear cranks thereof projecting outwardly from the respective front and rear faces of said crankcase, of mounting the front and rear connector rod assemblies onto the front and rear cranks respectively, of mounting the front and rear crankshafts onto the front and rear cranks of the center crankshaft respectively, of aligning said composite crankshaft by rotating the front and rear elements thereof relative to the center portion thereof, of locking said front and rear crankshafts to said central portion, and of then mounting the front and rear crankcases over and in housing relationship with their respective crankshafts and in abutting relationship with said center crankcasing for completing the crankcase assembly.

7. The method of assembling the power section of an internal combustion engine of the radial type which is characterized by a double bank of cylinders, and which includes a three" element c'relnksha'ft assembly comprising a central' crankshaft having front and rear crank portions and front and rear crankshafts mountable upon said c'renk portions, and a three element crankcase comprising front, center and rear elements wherein each element has a emainbearing receptive opening therethrough, which method comprises the steps of securing the center crankcase in an upstanding position, of mounting the cen ter crankshaft including its main hearing in the bearing receptive opening of the central crankcase with its front and rear crank portions p'ro-' j'ecting outwardly from the front and rear feces respectively of said crankcase, of mounting the front and-rear connecting rod assembly onto the front and rear cranks'respeotively, of then mount ing the front and rear crankshaft's onto the front and rear portions of, said center crankshaft, of aligning the three element crankshaft by rotat 12 mg the front andzrear crankshafts with and relative to the center shaft, of then mounting the front and rear orankcases over their respective front and rear crankshafts for completing the crankcase assembly.

THOMAS MCDANIEL, JR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS